The niobium pentahalides are known to be useful as catalysts in various organic reactions. See for example, Friedel-Crafts and Related Reactions, Volume 1, G. A. Olah, Ed., Interscience, 1963, New York. A means of providing niobium pentahalide distributed over a "support" would be very useful, both from an economic point of view and from a handling point of view. The main problem to date in supporting niobium (V) halides on a support is that the niobium pentahalides are basically only soluble in solvents in which they react and thus the usual techniques of impregnation to obtain a metal loading of niobium (V) halide can not be utilized. The instant invention provides a solution to this problem. The compositions of the instant invention provide for niobium (V) halide/oxide bound to the surface a metal oxide substrate.